The report looked at the entire life cycle of oil, from production to end use, and found some oils emit as much or more greenhouse gases as Canada’s oil tar sands.

“And those are the same oil sands that California didn’t want to take, because they were so dirty. But California produces some of its own really dirty oils,” says Deborah Gordon, director of the energy and climate program with the Carnegie Endowment.

The study also found California has some of the cleanest oils. Gordon says that’s because an oil’s chemical composition can vary.

“I was shocked right from the beginning at how wide-ranging these emissions were and how little we talk about oil [as] anything other than being an average standard barrel of oil,” Gordon says. “There are really big differences between oils, and that really conjures up the challenges involved in managing them well.”

The report says the state should track an oil’s chemical makeup to help better manage greenhouse gas emissions.

Amy came to Sacramento from New Hampshire Public Radio (NHPR) where she was Environment Reporter. Amy has also reported for NPR member stations WFAE in Charlotte, WAMU in Washington D.C. and American Public Media's "Marketplace." Read Full Bio